Abstract: The reliability is introduced to study net attack model by Petri net.The net attack model is considered as a system for research.Not only the truth degree of goal place is attained，and the dynamic reliability for attacking path and attacking system is analyzed.Then a new attack model，Dynamic Reliability Fuzzy Timed Petri Net attack model（DRFTPN） is presented，and the relevant reasoning algorithm combining with reliability is given.This model descripts attacking process as a non-repairable complex system，and presumes that attack states delegated by places are randomly failing.In order to calculate the system reliability，an approximate compensating algorithm to calculate the reliability life of system is given.And attacking paths of DRFTPN based on the minimal path sets are sought.Finally，DRFTPN is simulated by the Monte Carlo method.

Key words: fuzzy timed-Petri net, dynamic reliability, attack model, compensating algorithm, minimal path sets

摘要： 在利用Petri网方法研究网络攻击模型的过程中，引入攻击可靠性的概念，将网络攻击模型作为一个系统看待，以此系统为研究对象，不仅通过推理算法得到目标库所的真实度，并且对攻击路径和系统进行动态可靠性分析，从而提出一种新的攻击模型—动态可靠性模糊时间Petri网网络攻击模型（DRFTPN），并结合可靠性给出了相应的推理算法。这种模型将攻击过程描述为一个不可修复复杂系统，认为库所代表的攻击状态是随机失效的。为了计算复杂系统的可靠度，提出了一种近似求得系统可靠寿命的补偿性算法，并利用基于最小路集的方法求得DRFTPN模型的攻击路径。最后，运用Monte Carlo方法对DRFTPN模型进行仿真。

关键词: 模糊时间Petri网, 动态可靠性, 攻击模型, 补偿算法, 最小路集